With advances in and proliferation of communication technologies, content sharing has become commonplace. For instance, video communication has experienced increasing demand and has seen tremendous growth in popularity.
In video coding, intra/inter prediction is introduced to reduce the spatial/temporal redundancy inherent in video data. In inter prediction, at the encoder side, to code the current block, one or more previous reconstructed frames from the decoded picture buffer (DPB) will construct one or two reference frame lists for the current frame to find its most similar block. At the decoder side, based on the information in the bit stream, the decoder will find the corresponding reconstructed frames from its DPB and locate the corresponding block location in the reference frame for reconstruction.
There could be two kinds of reference frames, which are short term reference frames and long term reference frames. A short term reference frame will be removed automatically when the DPB is full or by an explicit command. However, a long term reference frame may only be removed by an explicit command. At the decoder side, once all the frame(s) in the reference list(s) for the current frame are found, the current frame may be correctly decoded.
Due to the network restrictions, there will always be packet loss during the transmission. When packet loss occurs, one possible way is to ask the sender to resend the packet again, which may take a long time to get the missing packet. However, for real-time video communication, live video communication or interactive video communication scenarios, this time delay might not be acceptable. Therefore, for these scenarios, when packet loss occurs, the current frame will be discarded and may not be used for future reference, which may cause the decoding problem for the subsequent frame(s) under the traditional reference frame management approaches. Especially, during the connection process, since the I frame is very large, it is very likely to have a high probability of packet loss. Therefore, how to establish the connection as quick as possible is also a very challenging problem.
Therefore, novel systems and methods are proposed to establish the connection and manage reference frames for video communication under the packet loss scenario, especially for real-time video communication, live video communication and interactive video communication.